Tyre, Lebanon: The ambulance headlamps were on, the blue light overhead was flashing, and another light illuminated the Red Cross flag when the first Israeli missile hit, shearing off the right leg of the man on the stretcher inside. As he lay screaming beneath fire and smoke, patients and volunteer ambulance workers scrambled for safety, crawling over glass in the dark. Then another missile hit the second ambulance.

Even in a war which has turned the roads of south Lebanon into killing zones, Israel's rocket strike on two clearly marked Red Cross ambulances on Sunday night set a deadly new milestone.

Six ambulance workers were wounded and three generations of the Fawaz family, being transported to hospital from Tibnin with what were originally minor injuries, were left fighting for their lives. Two ambulances were entirely destroyed, their roofs pierced by missiles.

The Lebanese Red Cross, whose ambulance service for south Lebanon is run entirely by volunteers, immediately announced it would cease all rescue missions unless Israel guaranteed their safety through the United Nations or the International Red Cross.

For the villages below the Litani river, the ambulances were their last link to the outside world. Monday, that too was gone, leaving the 100,000 people of Tyre district with no way of reaching hospital other than to take to the roads themselves, under the roar of Israeli war planes.

The fateful call to the Red Cross operations room came through at about 10pm - well after dark, a time when almost no Lebanese now dare venture out.

At the Red Cross office in Tyre, three volunteer medics dressed in their orange overalls, and got into their ambulance. The plan was to drive halfway, meet the local ambulance, and transfer the three patients to their vehicle to return to Tyre.

By Nader Joudi's reckoning, the ambulances had been stopped for barely two minutes. Two patients had been loaded: Ahmed Mustafa Fawaz, who had been hit by shrapnel in the stomach, and his son, Mohammed, 14. The volunteer attendant was just easing Jamila Fawaz, 80, inside and setting up a drip when the missile struck. He managed to get the old woman and the child outside, but there was no way to reach Mr Fawaz. "It was horrible," Mr Joudi said. "He was screaming, and we couldn't do anything."

One of the members of the three-man crew from Tibnin radioed for help when another missile plunged through the roof. Ambulance crew and patients retreated to the cellar of a nearby building, then waited to be rescued, trying as best as they could to help the injured. "Each of us treated ourselves. There was no light," said Kassem Shaalan, a medic from Tyre.

By the time patients and ambulance crew reached Tyre, Mr Fawaz was unconscious after losing one leg, and suffering severe fractures to the other. His son had lost part of a foot, and his mother's body was riddled with shrapnel. Mr Joudi had shrapnel wounds in his left arm, and Mr Shaalan cuts to the face and leg.

He was adamant that the ambulances, with their Red Cross insignia on the roof, were clearly visible from the air. "I don't think there can be a mistake in two bombings of two ambulances," he said.

Although the air strike marked the first time ambulances have been hit by Israel in this war, for Mr Shaalan and the other Red Cross volunteers it was only a matter of time. After two weeks of strikes designed to choke off possible supply lines to Hizbullah guerrillas, travel to many villages was just too dangerous. Coastal villages even within a few kilometres of Tyre are cut off. In some, corpses remain trapped in the rubble for days.

But nothing is more perilous than travelling by night, and no more so than just before midnight that Sunday when another Red Cross crew set off from Tyre to pick up their injured colleagues.

"I was trembling," said Ali Deeb, one of the volunteers on the mission. "It was too dangerous, and helicopters buzzing, and all through this, I am thinking one thing: the ambulance that left half an hour before you has already been injured, and you could be next." Later Monday afternoon, two missiles landed in the building across the road from the Red Cross office.